Data base system and load distribution control method

Abstract

A data base system according to the present invention has a data base including at least one table and executing predetermined data processing by accessing to the data base in accordance with transactions. The data base system comprises a plurality of management process for executing data processing in accordance with assigned transactions, a plurality of buffers respectively provided for the plurality of management process, for holding partial copies of the table as blocks, data management table for storing a number of blocks held by each of the plurality of buffers, and transaction control section for assigning the transaction to the management process corresponding to the buffer which holds the largest number of blocks on the basis of the number of blocks stored in the data management table.

What is claimed is: 
     
       1. A data base system having a data base storing a plurality of tables each having data blocks and executing predetermined data processing by accessing to the data base in accordance with transactions having information indicating a target table name, the data base system comprising: a plurality of processing means for executing data processing in accordance with assigned transactions;   a plurality of buffer means, respectively provided for said plurality of processing means, for holding partial copies of blocks in the tables stored in said data base;   memory means for storing a set of a block number, a corresponding table name, and a corresponding buffer means identifier for each of the blocks currently held in said plurality of buffer means; and   control means for deriving the target table name from the transaction, calculating a number of blocks corresponding to the derived target table name for each of said plurality buffer means by referring to the stored sets, and assigning the transaction to the processing means corresponding to the buffer means which holds the largest number of blocks.   
     
     
       2. A data base system having a data base storing a plurality of tables each having data blocks and executing predetermined data processing by accessing to the data base in accordance with transactions having information indicating a target table name, the data base system comprising: a plurality of processing means for executing data processing in accordance with assigned transactions;   a plurality of buffer means, respectively provided for said plurality of processing means, for holding partial copies of blocks in the tables stored in said data base;   first memory means for storing a set of a block number, a corresponding table name, and a corresponding buffer means identifier, for each of the blocks currently held in said plurality of buffer means;   second memory means for storing the number of transactions being now processed by each of said plurality of processing means; and   control means for deriving the target table name from the transaction, calculating a number of blocks corresponding to the derived target table name for each of said plurality of buffer means by referring to the stored sets, and assigning the transaction to the processing means corresponding to the buffer means which holds the larger number of blocks and is processing a small number of transactions.   
     
     
       3. In a data base system having a data base storing a plurality of tables each having data blocks, a plurality of management processes executing predetermined data processing by accessing to the data base in accordance with transactions having information indicating a target table name, and a plurality of buffers respectively provided for said plurality of management processes and holding partial copies of blocks in the tables stored in said data base, a load distribution control method of assigning transactions to said plurality of data management processes comprising the steps of: storing a set of a block number, a corresponding table name, and a corresponding buffer identifier for each of the blocks currently held in said plurality of buffers;   deriving the target table name from the transaction;   calculating a number of blocks corresponding to the derived target table name for each of said plurality of buffers by referring to the stored sets: and   assigning the transaction to the management process corresponding to the buffer which holds the largest number of blocks.   
     
     
       4. In a data base system having a data base storing a plurality of tables each having data blocks, a plurality of management processes executing predetermined data processing by accessing to the data base in accordance with transactions having information indicating a target table name, and a plurality of buffers respectively provided for said plurality of management processes and holding partial copies of blocks in the tables stored in said data base, a load distribution control method of assigning transactions to said plurality of data management processes comprising the steps of: storing a set of a block number, a corresponding table name, and a corresponding buffer identifier for each of the blocks currently held in said plurality of buffers;   storing a number of transactions being now processed by each of said plurality of management processes;   deriving the target table name from the transaction;   calculating a number of blocks corresponding to the derived target table name for each of said plurality of buffers by referring to the stored sets; and   assigning the transaction to the management process corresponding to the buffer which holds the larger number of blocks and is processing a small number of transactions.